Percussion fuse



April 7, 1925- C. P. WATSON PERCUSS ION FUSE Filed March 9, 1921gvwentoz LII - cnmferential groove CHARLES ATSQN. or mar na, camsoanre.

v atton'ssron' Fuse. I

" Application enam l- 1; a 1921, Serial No, 4,51 ,o0'2f To all 107mmz'tmay concern: a V 7 Be it known that 1,,Crmii1ms P. lVarsoN, a citizenof the United States,-.res1d1ng at Big Pine in the county of Inyo andState of California, have invented new and useful Improvements inPercussion Fuses, of-

which the following is a specification.

My invention relates to fuses such as are the accompanying drawings Iand will be hereinafter described.

In such drawings, Figure l is a central, vlongitudinal section of thefuse;

Figure 2 is a, longitudinal section taken on the broken line II, II ofFigure 1.

Figures 3, 4 and 5 are cross sectional viewsjtaken respectively on thelines III,

III. TV. IV and V. V ofFig. 1..

Figure 6 is a broken sectionallview i'llns ti'ating a modification.

Ifi the dlawifias he casing o fthe test is This is preferably for ddesignated 2. V p from cylindrical stock metal, cut to a proper lengthand bored out internally to form a, forward chamber 8, in which islocated the booster charge of the fuse, and a rear cham} ber 23 in whichare located theselveralzoper-' 'ative and functioning elements of thefuse,

which will be later described. The chamber 23 is divided by a partition12, having screwthreaded engagement with the casing 2,.into two parts,in the rear one of which. isflocated a plunger 20 carryinga firingpin21.: The rear end of the chamber 23 is left open, and. its wall near therear end is internally screw-threaded as indicated a133, to receive aclosing plug 6. This plug is provided with aflange 7, adapted to abutagainst and extend over the rear edge of-the cas ng, 52,

when the plug is screwed tightly into place,

and constituting the rear-end flange of the fuse considered as a whole.The fuse casmg is externally screw-threaded as indicated at 4 inproximity to the flange 7 such screw threads serving as the means foruniting the fuse with the shell or casing of the pro-' jec-tile. Theinner end of the closing plug 6 is formed with a cone shaped recess tore ceive and fit the correspondingly shapedend 5. It son'ietin eshappens that the case of the'fuse 'deform'ed l I by reason of-sid'eimpact of the projectile, with the result that the plunger, carrying theifiring pin, becomes jammed; orpinched and hence inoperative,renderingit imp'os; sible for the fuse to function and making the shelldead. Byweakening the casing'of 3 the fuse as described, any giving wayor' deforming of the fuse dueto side impact will naturally take place atthe. weakened zone thereof-where the circumferential groove 5 isformed-and as this is oppo site theconical end of the plunger, thedeforming of the fuse case will act to push forward the plunger 20,either causing the fuse to function immediately or 'else moving theplunger into a vpart of the chamber that remains in shape" andundeformed,

here it will be in :condition to function" immediately uponend-oniinpact of thepro jectile. v p

By constructing the fuse casing in the manner described I carnuse forthe major,

part thereof stock material the diameter of the body of the fuse, and atthe same time provide thefuse with an end flange 7. Heretofore; it hasbeen customary in manufacturing casing'si for fuses to use stock ma-'terial of a diameter equal to the. diameter of the end flange and to cutthis down tothe size which the fuse body. is to have, with" the resultthat "much machine work was v necessary in manufacturing such fuses andconsiderable waste material resulted. By

the use of my invent-ion; however, the only,

part of the. fuse that is made from stock materialof the diameter of theflange 7 is the short portion constituting the closing plug 6. i Y 7 Thebooster charge carried by the use is loaded into. the chamber 8, at itsinner end; The partition 12 is formed with a tubular extension 14. theend of which enters and tightly closes the opening '39 througlrthebarrier 38 that separates the booster chamber 8 from the chamber inwhich is. located the firing mechanismand the primer. A The end of theextension ,lat enters the opening 39, and-when properly seated thereinand heldin place by the engagement of the partition 12 with thewalls ofthe fuse casing or body, becomes, in effect, a part of the said barrierpartition separating'the chambers 8 and 23, and this barrier 'is ofsufficient strength to resist the effects of any acci-, dental explosionof'the prin' cr, orthat part of the detonating I train located in the"Ollttlllber 23, and prevents such accidentalflexplo sion from 7 settingoff the booster charge. ThI'OLI 'h the partition 12 and extending intothe tubular part: 14is a chamber for the primer and a, part ofthedetonating train of the fuse. The said train consists preferably 7 of acharge of compressed fulminate 16 be hinjdg which is a delay pellet 1,7,separating the compressed fulminate from the primer orpercussion .cap 18that is intended to be acted upon directly by the firing pin 21. Thedelaypellet 17 is formed of an explosive of such'lnature that it actsrelatively slowly,

serving'jto insure a slight delay; between the time the percussion capisignited and the moment the compressed mercury charge is fired, thusgiving tlieprojectile time to pass through armor before it is ruptured.In

the forward portion ofthe tubular part 14 is.formed a passagelointowhich is loadeda a train of'explosive constituting part ofthedetonating train and preferablyv formed of tetryl pellets oraneqnivalenthigh explo--- f sivel In order vtoget a detonation of theprojectile of high'ordeiyit is important that each successive-charge asit is ignited should be yiolently detonated, and I have devised severalimprovements to increase the inten-- sity of the successive detonations.The pas- 4 sage 15 does 'not extend directly through .to. the endv ofvthe projection 14.; It is rather divided, continuing as divergingpassages,

as indicatedin Fig.1. Into these passages are seated theends of adetonating cord,

that is a piece of fuse cord 13 carrying high explosive, theintermediate part. of the fuse cord 13 being in the form of a loopwithin the. chamber 8 and in immediate proximity to the 'boostercharge.The detonation of the explosivewithin the channel 15 acts to ignitesimultaneously the ends of the fuse cord 13.- The detonatingwavesincident to the combustion of this fuse cord, traveling at anexceedingly high velocity, meet at a point approximately the centerofthe fuse cord and in immediate proximity to the booster charge. Theeffect of this meeting of the detonatin waves a3 )roachin each otherfrom opposite directions, is to very greatlyintensify the'action of thefuse, as

compared with what it .would be if, for instance, the perforation 15extendeddirectly and entirely through the part 14, or if two independentpieces of detonating fuse cord were inserted in the diverging passagesat the end of the channel 15, and such detonating fuses terminated. incontact with, the booster charge but separate from each other,

In order to'make a fuse such as have described safe under allconditions, except when the progectile carrying itis fired from a gun,

I transversely perforate the tubular extension 14, as indicated at 26,the perforation 26 intersecting the longitudinal perforation 15 andbeing preferably of larger diameter than the latter. In the perforation26 is mounted a rotatory bolt 27 that is formed at one'end with an arm28 extending therefrom at substantially right angles, the end of thebolt opposite that carrying the arm 28 having a: head '29 that mayconveniently be formed by 'a' short, removable, large headed screw. ;Aspring 30 is interposedflbetweeni the bolt 27 and the tubular extension14 and acts-as a means to hold the bolt normally in safety position. Thespring illustrated. is constructed and arranged so that it acts both asan expansion spring and as a torsion spring- It is a coiled springsurrounding the stem of the bolt'being preferably partly seatedinarecess 32 formed therefor in the part14, and is at one end connectedwith the bolt, and at itsother end with the partdirection to bring thearm 28 against the tu- 14. The expansive action of the spring op-'erates. to move the bolt longitudinally .in a

bularextension 14, whichlatter is provided with a shallow recess 31 inwhich the end of thearm rests, as represented in F ig. 1, being therebyheld in the-position indicated. The torsional action of the springoperates torotate the bolt in such a way that the arm 28 thereof liesparallel with the tubular "extension 14 and'seated in the recess 31,asrepresented in Fig. 1. There isa .diametric perforationn33 through thebolt '27, this being so located that whenthe bolt is in the positionindicated inFig. 1 and in full lines in a prematureor accidentalexplosion of the primer the detonating effects thereby. produced will.not be communicated to'the booster charge and through it to thebursting charge ofthe shell, but will be confined to the chamber 23, thewalls of which are sufficiently strong to withstand the: pressures vincident to such an accidental explosion. In.

order that, the pressures incident to any such accidental explosion maybe dissipated as'far as possible the partition 12 is perforated, asindicated at 35, permitting the gases that would be generated tojexpandinto the chamber 23 on 'both sides of the parti-' tionQ a v I refer tothe bolt 27 as rotatory though it is permitted to turnupon itslongitudinal eentral'axis, infunctioning as has been described, only apartial revolution.

The plunger 20 'carries the firing pin.

This may-be of any preferred'style to insure safety. I prefer thatitshould be moved into armed or firing position by a pair ot=- theplunger is located and acts to" hold the forineragainst partition 12undernormal conditions, to permit it to set back when the shell is firedfrom a gun.

The operation of the fuse is as follows? The parts of the fuse arenormally-in the positions indicated in Figs. 1 and 2*; the firing pinbeing retracted and within the, body of the plunger, its pointed endbeing below the forward face-thereof so that, should the plunger moreforward, the primer will not be acted upon, and the/bolt 27f, resting 1nsafety position, will cut off comm'uniea tio'n between the chamber wherethe primer is located and that in which the booster charge is placed.Upon the shellbeing fired. centrifugal force, developed the rotation ofthe shell in its flight,causes the firing pin to be projectedforwardfandtheplunger 29. i0:

become armed, in the manner describedfliu my aforesaid patent. Furtherdescription of this is therefore unnecessary;

The operation of [the safety bolt 27 is as follows: During the movementof the shell through the bore of the gun and. for some distance beyondthe muzzle thereof, the shell;

is bein violentl I accelerated [with the result that inertia. acti'ngupon the free eccen trically disposed arm 28 of the bolt, causes it tolie in the line of the flight of the shell that is parallel with theprojection 1d and as represented in Fig. 2. As soon, however,

as acceleration ceases, any tendencyfor the.

arm to remain inthis position, due to. inertia, ceases. Centr fugalforce, generated by the rotation of theprojecti-le, acts uponv themovable bolt 27, and the disposition "of the weight of the partsth'ereof'is such that this force tends to move the bolt 'longitu-fdina-lly in its seat in a. direction-to ca1'ry the arm 28 awa from thepart 14, thus releasing.

it from the recess3l and compressing the.

spring 30'. Centrifugal force now,.a cting on the arm 28, causes thebolt to be rotated into the position indicated in dotted lines in Fig 2'with the arm sticking'out' or projecting at,

right angles to the axis of the line of flight of the shell. Thesemove-ments'of the bolt,:

due to the act-ionof' centrifugal force thereon-first longitudinalmovement freeing the arm 28 from the recess 31, and then rotatix e a rumto stand trans:

movement causing the verse tothe of flight%brings. the perforation'33into line with g the l perforation 15, thus removing the barrierthatnormall rendered the fuse safe against explosion due to the firing ofthe primer. P

It ,will'be seen that notfonly is a fuse, constructed according tomyzpresent' invention and: in the manner described and illustrated inthe accompanying drawings, safe under normal conditions, but it alsopossessesbore of the severalparts' of the bolt 27 are such withinthebore of the gun and while itsv speed offlight is being accelerated, is;

stronger than is the centrifugal. forcedue to the rotation of the shell,so that the lat- I ter' can not become eH'Fecti-Ye to arm the fuse,

by removing thebarrier cutting olf' the.

booster chamber, until, after the projectile ceases to accelerate inspeed, which does not safety, because the'disposition of the Weightsthat the force of inertia, acti:ng. upon the eccentric arm oftheboltWhile the shell take place until the projectile has progressed somedistance beyond themuzzle of thegunQ It! wil l beunderstood that aturret bolt 27,.

arranged similarly to that shown: in the drawing except that it is notfree :t0 1n'otelongitud nally in its seat, would: beelfective andoperate successfully as' a safetycnt-ott between" the chamber containingthe primer and tihat in which is locatedi the boostercharge,- but thearrangement shown'has oer? tain adwa ntages, asit gives a doubleelein'ent' ofsafety. V v

Such a turret bolt as: that just referred to is represented in In this;View the eccentric-arm- 28bit the. turret bolt is posi-v tively held innormal safety position by a locking 'b'olt 34s, one end of which. isseated 1n a recess 3'} in such arin and; its. other: en d 111arecessformed in thepart-itlon L2. A sphtelastic ring 36-.surround-1ngthe bolt tends to holdit in normal locking; position. but yields .upon.the set back of the belt at the instant of firing the shell permittingthe bolt tec'nterthe recess 35ijwhere it is held by: thespri-ng. 36,.-leaiiing the tairiret bolt free to, function ashas been described Havingdescribed. my invention, what I claimfis 1. A fuse for ordnanceprojectiles, comprising acasingin which is formed a chamber,

a movable plunger located in said chain;

ber. adapted to function upon; impact of the shellto firetl1e"fuse,.and; the outer wall ofl the'. fuse casing. enclosing thechamber therein being weakened toward the rear of, the chamber,whereby-should; the fusejbe deformed by reason of. side impact ot theprojectile in flight, the casing ill;yiel.d;a,t the weakened part, andsuch. weakening will be inarear of the plunger soas not to inter ferewith its functioning, a

'2; A fuse for ordnance projectiles; com

prising a casing in which is located a m,ov

able plunger carrying a firing jpin, the plunger being 1nvpart coneshaped, and the fuse. casing ,belng circumferentlally weal:-

ened in the portion lying outside theconfc;

shaped part of theplunger, whereby should the fuse deform byreasonofside impact of the projectile its casing willgive way at the saidweakened part and such giving way will cause the wall of the casing. toact on.

the conical portion of the plunger to move itinthe directionvfor firingthe fuse.

'3. A fuse for ordnance projectiles, comprising a-casing chambered-toreceive and carry in one part a booster. charge of eXplo sive, and inanother mechanism for firing-the charge, a barrier separating the saidcharge and mechanism chambers,,through which is formed a passage thatdivides into two separated parts toward the chamber for the boostercharge, a detonating fuse cord located in the said passage and extendingthe're-' from in the form of a-loop into proximity to the charge to bedetonated, the end portogether .in the undividedpart of such passagewhile theloo-p extends beyond the bar- 1 rier, and means .forsimultaneously igniting ,thesaid portions of the fuse cord that aretions of the cord being carried respectively through-the twoseparatedparts ofthe passage through the barrier and 'then brought broughttogether, whereby detonating waves due to the combustion of thesaidcord, starting from the place of ignition thereof, conducted,through the separated passages in the barrier, and meeting in the loopedportion of the cord outside the barrier,- cause the action of the fuseto be intensified. V

4. 'In a fuse for ordnance projectiles, a casing chambered toreceiveandcarry in one 7 part a booster charge of explosive andgin another part mechanism .for firing the, said charge, a barrier interposedbetween the eX- plosive charge and the firing means, and an casingchambered to receive and carry in one part a booster charge of exploslveand in another part mechanlsm for firing the charge, a tubularconnection interposed between the explosive charge and the firing meansand an oscillating turret bolt support-" ed transversely in the saidtubular connection and serving as a safety cut-oft between the boostercharge and 'the'means for firing.

it, the turret bolt having an armnormally lying outside the tubularconnection, and the bolt being arranged when oscillated out of normalposition to establish connection 5. In a fuse for ordnance projectiles,af

between the booster chargeand the firing means, the force of inertia,due to acceleratlon of the sp'eed1offlight of the projectile carryingthe fuse','a'cting on thearm of "the turret bolt tohold it in safetyposition, and

centrifugal v force, due to the rotationofthe' proyectile -in flight,acting. onthe arm oscillating the turret bolt.

-6. 111a,.fuse for" ordnance projectiles, a

chambered-casing carrying a. booster charge and means for firing suchcharge, a tubular connection interposed between the charge .anditsfiring means, an oscillating turret bolt adapted to serve as a safetycut-off in the said tubular connection, the turret bolt being arrangedto be oscillated by the ac-. tion of centrifugal force due to therotation of the projectile in flight to armthe fuse,

and a spring acting on the saidturret bolt tending to hold it m safetycutoff position, but arranged to yield'when the turret bolt -issubjected to centrifugal forc'e and permit thefuse to be armed. 1

7.; In a fuse for ordnance projectiles, a cas ing chambered toreceiveand carry a booster charge and the. firing me-ans, an oscillating turretbolt transversely supported in the said tubular connection and arrangedto serve as. a safety cut-off to interrupt the tubular connection, theturret :bolt being supported so as to be movable to a limited extentlongitudi-' nally, and a combined expansionand torsion spring acting onthe said bolt for holding it in safety position, the bolt having aneccentrically disposed part adapted to be act ed upon by centrifugalforce when the fuse;

. charge and] means for firing suchcharge, a tubular connectioninterposed between the 'lou is .in rotation during the flight of thepro-:

j ectile, such'centrifugal force tending to move the turret bolt[longitudinally in its seat against the action of the, said spring, and

also tending to cause it to oscillatefalso against the action of thesaid springrthe movements of the turret bolt operating to arm the fuse,putting thefiring means into communication with the booster charge.

8. In a fuse, the comb nation of a rotatory part having an "eccentricarm at approxi- Y mately right angles thereto and adapted to occupyeither a safety or an armed position, Whereby'inertia acting on theeccentric arm due to the acceleration of a shellcarrying .the fuse tendsto hold the part in safety position, and centrifugal force due to therotationv of the shell in flight actingon the arm tends to move the partto armed position. .9. Thecombination stated in claim 8, in-,

eluding also means that maintain the said rotatory part in safetyposition under normal conditions. v

10.111 a fuse the combination. of a rotatory cylindricalpart adapted .tooccupy either a safety or an armed position, the said part having aneccentric extension whereby inertia due to the acceleration of a .shellcarrying the fuse tends to hold the part in safety position, andcentrifugal force due to the rotation of the shell in flight tends torotate the part about its longitudinal axis to armed position.

11. In a fuse, the combination of a rotatory cylindrical parttransversely supported relative to the axis of the fuse and adapted tooccupy either a safety or an armed position, the said part having aneccentric extension where-by inertia due to the acceleration of a shellcarrying the fuse tends to hold the part in safety position, andcentrifugal force due to the rotation of the shell in flight tends torotate the part about its longitudinal axis to armed position.

12. The combination stated in claim 10, including also means thatmaintain the rotatory cylindrical part in safety position under normalconditions.

13. In a fuse, the combination, of a rotatory cylindrical parttransversely supported relative to the axis of the fuse and adapted tooccupy either a safety or an armed position= the said part having aneccentric extension whereby inertia due to the acceleration of a shellcarrying the fuse tends to hold the part in safety position,andcentrifugal force due to the rotation of the shell in fli ht tends tomove the part laterally and to rotate it about its longitudinal axis toarmed position.

H. The combination stated in claim 13, including also means thatmaintain the rotatory cylindrical part in safety position under normalconditions.

A high explosive detonating fuse formed with a chamber to receive adetonating charge and another chamber in which are located the primerand the movable functioning parts that fire the primer, these elementsbeing connected by a channel of communication, a rotatory cylindricalbolt supportedso as to intercept the said channel and constitute aclosing barrier between the chambers when moved to safety position, thebolt being formed with a passage arranged to register with andconstitute part of the channel of communication when the bolt is rotatedto armed position.

16. The combination stated in claim 15, including also means for holdingthe said bolt in a predetermined position.

17. In a fuse, a rotatory part turning about an axis that is transverseto the longitudinal axis of the fuse and the shell that carries it,arranged to occupy either a safety or an armed position, means forholding the said rotatory part normally in the safety position butarranged to be operated to release the rotatory part upon the shellbeing fired from a gun, and a spring acting upon the rotatory part andtending to move it to safety position.

18. In: a fuse, a functioning element comprising a transverse rotatorypart arranged tooccupy either a safety or an armed position, a coiledspring surrounding the said rotatory part and having one of its endssecured thereto and the other end secured to a non-rotating part of thefuse, the spring being arranged to act on the said rotatory part to moveit to-safety position, and means to normally hold the part in safetyposition arranged to be moved to release the part when the shell isfired from a gun.

19. In a high explosive detonating fuse formed with a chamber to receivea booster charge and another chamber in which are 7 located the primerand the movable functioning parts that fire the primer, these chambersbeing connected by a channel of communication, a rotatory bolt supportedso as to intercept the saidchannel and to constitute a closing barrierbetween the chambers when moved to safety position, the bolt having adiam-etric passage through it arranged to register with and constitutepart of the channel of communication when the bolt is rotated to assumearmed position.

20. In a detonating fuse, a fuse body having a chamber in which islocated the booster charge and another chamber separated therefrom inwhich is located the primer and the firing means, and a channel ofcommunication between the said chambers, means arranged to cut off thesaid channel of communication when occupying a safety position and toleave the same open when occupying an armed position, a charge ofdetonating explosive for the booster charge to be ignited from theprimer chamber when the said channel of communication is open, arrangedin front of the saidcut-oif means, and means to direct and intensify theeffects of the said detonating explosive where it directly acts upon thebooster charge.v

21. In a detonating fuse, a fuse body having a chamber in which islocated the booster charge and another chamber separated therefrom inwhich is located the primer and the firing means, and a channel ofcommunication between the said chambers, means arranged to cut off thesaid channel, of colmnunication when occupying a safety position and toleave the same open when occupying an armed position, a detonating trainof high explosive material. between the primer and the booster charge,which train is divided by the said cut-off means, the portion of suchexplosive train to the rear of the cut-off being surrounded by anexpansion chamber, and the portion in front of the cut-oif beingarranged so that its explosive effect is directed to intensify itsaction on the booster charge.

CHARLES P. 'WATSON.

